"This is extremely tough for all of us," trainer Doug O'Neill said at a hastily called, packed press conference as I'll Have Another grazed a couple of yards behind him. "It's far from tragic — no one died or anything like that — but it's extremely disappointing and I feel so sorry for the whole team."

Though I'll Have Another could have run, O'Neill and Reddam said, it would not have been in the best interest of the horse. And though he will heal with a few months of rest, they feared he'd never return to his current form.

So I'll Have Another will lead the post parade before the Belmont on Saturday — on-call veterinarian Larry Bramlage said doing so will not endanger the horse — giving what will undoubtedly be a diminished crowd one final look at racing's latest would-be star. Dullahan is now the 9-5 favorite in the afterthought of a race.

Members of Team O'Neill — the robust group who has accompanied the colt on his cross-country journey from California to Kentucky to Maryland and then here — noticed some loss of muscle tone in the horse's left leg Thursday afternoon. There was warmth in the area, too, but it dissipated quickly. O'Neill hoped I'll Have Another had bumped the leg and developed a meddlesome but basically harmless skin irritation. The trainer's crew wrapped it with a special poultice, and took the horse to the track.

Prior to revealing the injury, O'Neill said the impetus for the early morning session had been to keep the horse relaxed. The crowded Belmont Stakes barn was too hectic around 8:30, when the track was reserved for horses in the Belmont. Nevertheless, his workout under the cover of darkness stirred rumors that the horse could be injured.

"This morning, he looked great," O'Neill said. "So I thank the racing gods there. … And then, cooling out, you could tell the swelling was back and at that point I didn't feel very good."

A track veterinarian examined the colt and gave O'Neill the diagnosis, and the decision to pull the chestnut colt and retire him was immediate and "unanimous," O'Neill said.

The charismatic trainer dominated much of the news during the Triple Crown chase, not only because of his out-sized personality but due to past struggles. A few days after winning the Preakness on May 19, O'Neill was given a 45-day suspension by California racing officials for running a horse with a high total carbon dioxide level in 2010. He'd been fined three other times for the same thing, and The New York Times also reported his horses had broken down at nearly twice the national average.

Reddam made a point of saying that O'Neill put I'll Have Another's well-being first.

"It wasn't like he had an injury and Doug took him out for a test drive this morning," he said.

"I think he was sort of stunned," Reddam said, "Because he really didn't say much at first, and I wasn't sure that he really understood what I was talking about."

Maryland-based veterinarian Dr. Nick Meittinis, who regularly examined I'll Have Another while he was at Pimlico, said the colt was completely healthy coming out of the Preakness. The injury most likely would have been caused by a sudden movement or a step over uneven ground going at a fairly high rate of speed.

"Horses are very fine-tuned machines, and when one thing gets shifted the wrong way, there can be trouble," he said. "I'm not going to blame the loose horse" that nearly side-swiped I'll Have Another during training last week, "but it's that kind of movement, causing a horse to veer suddenly, that can cause that one area to be overstressed."

Though there is no truly analogous tendon in humans, I'll Have Another's injury is similar to an Achilles tendon strain, Meittinis said. The colt could have raced without even noticing the pain; he also could have broken down.

"Nobody would have wanted him taken out in an ambulance," Meittinis said.

He thought the detention barn would not have contributed to the injury "unless the horse felt anxious and did something he wouldn't usually do on the track."

O'Neill, who'd been critical of the barn where all of the Belmont competitors were sequestered and subjected to constant supervision, said it "absolutely" did not contribute to the injury.

"Just a freakish thing," he said. O'Neill also thought the strain of running two races and training for a third in five weeks did not cause the injury. Many of his fellow trainers, in fact, thought he went too lightly on I'll Have Another since winning the Preakness.

Former jockey Richard Migliore, who had offered advice to Gutierrez, said the news, at first, nearly leveled him.

"I really thought for a few minutes that I was going to cry," he said. "But the important thing is, he's going to be a daddy and we'll see how the little I'll Have Anothers run."

O'Neill fell in love with horse racing as a kid, taking buses to tracks in Southern California before he was a teenager. He, Reddam and the rest of their crew plan to stay for the Belmont. Their horse will ship Sunday or Monday, as originally planned.

"Look, the races are going to go on today," Reddam said. "The big race is tomorrow."

Indeed, as I'll Have Another left the Stakes barn and moved toward a stall a few stables away, the other horses, perturbed by the parade of journalists, volleyed neighs back and forth. Stable hands accustomed to tranquillity stared blankly at the procession. Word of the flaring tendon had spread to them hours before.

Near the park, bettors ruffled through their Daily Racing Forms — prematurely antiquated, with covers showing a horse in full stride who will never be that way on a track again — and looked over the colts getting ready to run the third race.

The absence of Derby and Preakness winner I'll Have Another opens up the 2012 Belmont Stakes from a wagering perspective. Dullahan and Union Rags are likely to be co-favorites, with Dullahan possibly taking slightly more wagering. The Union Rags faithful still believe he is one of the top...

A record Preakness crowd saw the Kentucky Derby winner streak to victory Saturday at Pimlico Race Course, tantalizing fans with the possibility that California Chrome will be the first horse in nearly four decades to win racing's coveted Triple Crown.